HELP!!! Charging issue. - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sacaledus · 08-24-2009, 01:43 PM

Thank you in advance for any and all help. Well I have a 1979 C20 with the 5.7L 350. It runs good but I am encountering a charging issue. New battery, all connections look good, alternators been tested both on and off vehicle and passes. Here's the issue. Everytime I jump on the freeway I get a dip in voltage. Lately it's been into the red. One night it dropped down so far I pulled to the side of the road and let id idle and it jumped up just past 13 then came back down to just below. Put it in gear to take back off and it begins to drop. Got it home and at idle jumped back up to 13 and stayed while idling. Any ideas??

87Bob · 08-24-2009, 01:44 PM

Quote:

Originally Posted by sacaledus

Thank you in advance for any and all help. Well I have a 1979 C20 with the 5.7L 350. It runs good but I am encountering a charging issue. New battery, all connections look good, alternators been tested both on and off vehicle and passes. Here's the issue. Everytime I jump on the freeway I get a dip in voltage. Lately it's been into the red. One night it dropped down so far I pulled to the side of the road and let id idle and it jumped up just past 13 then came back down to just below. Put it in gear to take back off and it begins to drop. Got it home and at idle jumped back up to 13 and stayed while idling. Any ideas??

Have your alternator tested. If you can find a good shop in town that actually does rebuilds let them to do the testing. Many times the ones that come from auto parts stores are junk (even ones that they offer lifetime warranties). What do they care if you spend an hour ot two changing them out each time.

Adams74Chevy · 08-24-2009, 05:08 PM

Quote:

Originally Posted by 87Bob

Have your alternator tested. If you can find a good shop in town that actually does rebuilds let them to do the testing. Many times the ones that come from auto parts stores are junk (even ones that they offer lifetime warranties). What do they care if you spend an hour ot two changing them out each time.

+1
Last alternator my father had rebuilt at a "good" shop (turns out they changed ownership after the last time we were there) they rebuilt the alternator and it overcharged to the point it cooked the battery popping the tops off of it and bubbling acid out onto the hood and overloading the computer.

Definately make sure they're a good rebuilder.

wydomkr · 08-24-2009, 05:46 PM

Maybe at the higher highway speeds and RPM the belt is slipping?

**old Rusty C10** · 08-24-2009, 06:09 PM

the regulator inside could be bad at high rpm im betting its the alternator... for giggles change it with another and see what happems

sacaledus · 09-03-2009, 11:40 AM

Turns out it was the belt... Go figure. Changed it out with a new gator back and Pow! Voltage looks wonderful. No dips when all accessories are on. Thanks!

silvereagle07 · 09-03-2009, 12:04 PM

Glad you found the problem. Usually if the regulator was bad, you would notice it at idle.

08-24-2009, 01:43 PM	#1
sacaledus Registered User Join Date: Aug 2009 Location: Everett,WA. Posts: 11	HELP!!! Charging issue. Thank you in advance for any and all help. Well I have a 1979 C20 with the 5.7L 350. It runs good but I am encountering a charging issue. New battery, all connections look good, alternators been tested both on and off vehicle and passes. Here's the issue. Everytime I jump on the freeway I get a dip in voltage. Lately it's been into the red. One night it dropped down so far I pulled to the side of the road and let id idle and it jumped up just past 13 then came back down to just below. Put it in gear to take back off and it begins to drop. Got it home and at idle jumped back up to 13 and stayed while idling. Any ideas??

08-24-2009, 05:46 PM	#4
wydomkr Registered User Join Date: Mar 2006 Location: Rapid City, SD Posts: 96	Re: HELP!!! Charging issue. Maybe at the higher highway speeds and RPM the belt is slipping? __________________ Keith ------------- 1980 C-10 1981 C-30

08-24-2009, 06:09 PM	#5
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	Re: HELP!!! Charging issue. the regulator inside could be bad at high rpm im betting its the alternator... for giggles change it with another and see what happems __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

09-03-2009, 11:40 AM	#6
sacaledus Registered User Join Date: Aug 2009 Location: Everett,WA. Posts: 11	Re: HELP!!! Charging issue. Turns out it was the belt... Go figure. Changed it out with a new gator back and Pow! Voltage looks wonderful. No dips when all accessories are on. Thanks!

09-03-2009, 12:04 PM	#7
silvereagle07 Registered User Join Date: Sep 2008 Location: Bailey, NC Posts: 2,462	Re: HELP!!! Charging issue. Glad you found the problem. Usually if the regulator was bad, you would notice it at idle. __________________ Jeramy '84 GMC project truck '85 Chevy 4X4 SOLD '07 Chevy Trailblazer SS 5th Annual SHPHC Car/Truck Show Pics http://67-72chevytrucks.com/vboard/s...d.php?t=543605 UPDATED PICS! CHECK 'EM OUT



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